Carbon-concentrating mechanisms in acidophilic algae
Carbon-concentrating mechanisms in acidophilic algae
复制标题
嗜酸藻类的碳浓缩机制
作者：
M. Díaz;S. Maberly
毫米。迪亚兹和 S.C. 马伯利。 2009.嗜酸藻类的碳浓缩机制。藻类学 48：77-85。 DOI：10.2216/08-08.1 从巴塔哥尼亚的天然酸性湖泊和河流系统中分离出七种系统发育多样化的微藻菌株。大气含氧量下 CO2 的半饱和常数在 2 至 12.7 µmol L−1 之间变化。 Watanabea sp 的球体形式的 CO2 吸收对氧敏感。 （Trebouxiophyceae），棕榈属 sp。 （绿藻纲）和一种未鉴定的 Prymnesiophyte，但对椭圆体形式的 Watanabea sp 不敏感。和眼虫门（Euglenophyta）。动力学证据表明棕榈科植物中不存在碳浓缩机制（CCM）。和 Gloeochrysis sp。 （Chrysophyta）和 Watanabea sp 的球形形式。但以 Watanabea sp. 的椭圆体形式存在。未鉴定的 Prymnesiophyte 中的低 K½，2 µmol L−1 表明可能存在 CCM，但动力学响应对氧敏感；然而，K½ 不受氧气的影响。 E. mutabilis 的碳吸收对氧不敏感，但 K½ 为 6.4 µmol L−1，这使得 CCM 存在的诊断不明确。 Watanabea sp 的结果。这似乎是第一个同一物种的不同形式在相同条件下生长时拥有或缺乏 CCM 的情况。 Watanabea sp.（主要由球体组成）的生长速率在空气平衡 CO2 浓度（取决于氧气浓度）下最大速率的 86% 至 95% 之间。即使在明显不存在 CCM 的情况下，这些物种对 CO2 的高亲和力表明，当酸性湖接近大气平衡时，光合作用和生长速率不太可能受到 CO2 的限制。
M.M. Diaz and S.C. Maberly. 2009. Carbon-concentrating mechanisms in acidophilic algae. Phycologia 48: 77–85. DOI: 10.2216/08-08.1 Seven phylogenetically diverse strains of microalgae were isolated from a naturally acidic lake and river system in Patagonia. Half-saturation constants for CO2 at atmospheric levels of oxygen varied between 2 and 12.7 µmol L−1. CO2 uptake was oxygen sensitive in the spheroidal form of Watanabea sp. (Trebouxiophyceae), Palmellopsis sp. (Chlorophyceae) and an unidentified Prymnesiophyte but insensitive in the ellipsoidal form of Watanabea sp. and in Euglena mutabilis (Euglenophyta). The kinetic evidence suggests that a carbon-concentrating mechanism (CCM) is absent in Palmellopsis sp. and Gloeochrysis sp. (Chrysophyta) and the spheroidal form of Watanabea sp. but present in the ellipsoidal form of Watanabea sp. The low K½, 2 µmol L−1 in the unidentified Prymnesiophyte suggests that a CCM may be present, but the kinetic responses were oxygen sensitive; although, K½ was not affected by oxygen. Carbon uptake in E. mutabilis was not oxygen sensitive, but the K½ was 6.4 µmol L−1, which makes the diagnosis of the presence of a CCM equivocal. The results for Watanabea sp. appear to be the first where different forms of the same species possess or lack a CCM when grown under identical conditions. Rates of growth of Watanabea sp., largely comprising the spheroidal form, were between 86 and 95% of maximal rates at air equilibrium concentrations of CO2, depending on the oxygen concentration. The high affinity of these species for CO2, even in the apparent absence of a CCM, suggests that when an acid lake is close to atmospheric equilibrium, rates of photosynthesis and growth are unlikely to be limited by CO2.